Plasma androstenedione (A) and plasma renin activity are measured to monitor treatment of patients with CAH. Plasma cortisol, adrenal androgens (A, testosterone, dehydroepiandrosterone) are measured; blood is gathered at 6-12h intervals for 1-3 days in infants and by constant withdrawal pump for 24h in older children with CAH, Cushing's syndrome, and virilizing tumors. ACTH test is performed to detect cryptic forms or carriers of CAH.